Michael j



hmw/ar ma /J. 1141/8 mm; runs Inc, ummvuwummc Patented Sept. 9, 1919.

MICHAEL J. wnrsn, or nonsense, ounnnc, cannon.

METHOD OF CASTING fiTRAP-BACK BRAKE-SHOES.

Specification of Letters Patent;

Patented Sept. 9, 1919.

Application filed November 9, 1M7. $cria1 No. 201,159.

To all whom it may concern Be t known that I, Micnnicn J. Waiisn, a

subject of the King of Great Britain, and

in method of castingbrakeshoes and other articles, and more especially to a method of casting articles in which some member is located in the mold, soas to be incorporated in the casting. This method will, therefore,

apply particularly togthe casting of strap.

back brakeshoes.

The object of the invention is to provide a simple and expeditious method of casting articles in metal, which will yield a high grade ofoutput.

A further object is to provide a method of securing inserts in the, mold, so that they ina be incorporated in the castings.

ll has been customary in the past to cast articles such as brakeshoes on end, but it has been found that this method is liable to produce poor castings. Articles which are required 111 large numbers Withsmooth surfaces are frequently cast in metal molds. These molds are in themselves rigid, and also have a certain definite expansion and contraction which must be taken into consideration, as well as the expansion and contraction of the metal poured into them.

When articles such as liirakeshoes are cast on ond,lihe cope and drag of the mold are usually tightly secured together to prevent the formation of fins on the casting at the part :ing line of the molds. This does not ermit of any relative movement of the mole parts with the expansion and contraction of either themselves or the metal poured into thenu Attempts have been made to overcome this by pressing one of the parts against the other by means of springs or elastic fluid such as air,.but the results produced by such methods are not entirely satisfactory. Springs lose their temper and power when they become heated, and the other appliances are cumhersome, complicated and expensive. lthas also been proposed to make molds which are expansible and contractible in all directions, in order to acconnnodate the mold to the e3.- patnsion and contraction of the metal poured in o it.

According to this invention, a mold is produced having the ability to expand in one or two directions,'0r possibly in both directions simultaneously. The mold is the subject matter of application 201,160, filed Nov. 9, 1917. lnrcasting elongated articles, it is obvious that most of the expansion will he in the longitudinal direction and that any tendency to expansion in other directions will readily convert itself to expansion in the longitudinal direction, the mold rigid in the transverse direction but free, to expand longitudinally. The mold is disposed in an inclined position, so that the cope is supported on the drag and presses down on the same by the action of gravity. The cope forms one end of the mold and the drag forms theopposite end, so that when the metal poured into the mold. expands, the cope may slide slightly on the drag and yield to the expansion, thus over coming the necessity for expansihility in other directions, and preventing the cope from being lifted oil' the drag by the expansion of metal or the metal being forced. into the parting line so that fins are pro* duced on the casting. ed in an inclined position, the inclination being such that the metal will run freely The drag is support 7 to the lower end of the mold, and also such that the cope will rest solidly on the drag.

In order to enable the expeditious carrying out of the method, the molds may he ar- "anged in batteries, the drags being suitahly supported and the copes being provided with means for quickly lilting them to ricmove the casting and permit the mold to cool.

In casting strap back brakeshoes, great difiiculty has been experienced in supporting;

the strapback in the mold, so that it presses tightly against the mold and prevents the entrance of molten iron between it and the mold. Difliculty haslalso heen'experienced in accurately positioning'the strap back in cope is reduced to a minimum. The position in which the hrakeshoe'is cast enables external means to be used for supporting the strap back 111 the mold, so that all 111- ternal supports may be dispensed with. The

m nned casting-position also on to a inmlmum the possibility. of molten iron escaping through the mold opening necessary shoe mold.

, Fig. 2is an end elevation thereof. sF 1g. 31s a section on the hue 3-3, F1g. 1. Referring more particularly to the draw- -ings, l1 designates the drag and 12 the cope of a brakeshoe mold. The drag is provided with an end member 13 overlapping the ,endofthe cope, and provided with a groove or runner lei through. which the molten metal is led into the mold. The cope is provided at the oposite end with an end member .15 which overlaps the end of the drag. The cope and drag may no provided on the longitudinal edges with interengag ing flanges or ribs 16 which will hold the cast.

parts in proper alinement, but obviously will not prevent relative longitudinal move ment. The parting line, designated l7, may be anywhere desired, and will be located according to ,the shape of the article to be In a brakeshoe, it is preferably located between the face and back usually nearerthe back than the face. The drag is secured to any suitable support 18, while the cope is provided with any suitable means .19; for raising and handling same. To enable the back strap, designated 20, to be supported in the mold prior to and during the casting operation, a large recess is formed in the copehaving an opening 22 which communicates with the interior of the mold, and through which the loop of the back strap projects, the opening being preferably of such size that the loop fits snugly therein, so that the molten iron will not be able to flow up between the loop and the cope. The loop isvprovided with open- 50.

ings 24ifor keying the brakeshoe to a brake head, and these openings are made use of to secure the strap back in the mold in the fOllOWillg manner Hooks 25 of any suit able size and shape are provided which pass "through the recess 21 and engage in the openings 24; oft-he loop. These hooks may be supported in any sultable manner, such as by a taper pin 26 which passes through eyes 27 on the hooks. Preferably, though not necessarily, the pin is tapered, so that it may be easily inserted and will draw the strap back tightly against the cope. In

order to insure proper positioning of the back strap 20 and a uniform tension on the hooks 25, the outer surface of the cope may applied to other ar-' he provided with a slight depressions, for

the reception of the pin 26, so that the pin will always be located in exactly the same spot. a v I I In carrying out the manufacture of brakeshoes according to thisprocess, a back strap 2O is inserted in the cope, while the same is 'molten iron will not enter between the strap and cope. This close engagement of the back strap and cone is particularly important around the opening 22, as, the strap acts as a seal for this opening and prevents the molten iron escapingtherefrom into the recess'21, To guard against any leakage of molten iron through the opening 22 due to a badly formed hack strap, a small amount of sand, designated 29, may be thron into the recess and the cope slightly agitated to cause the sand to work through the openings 2i of the strap loop and entirely fill the lower part of the recess 21. The cope is lowered on the drag where it fits accurately by reason of the interengaging flanges 16 and the ends 15 and 15. The

molten metal poured in through the runner 1-1: which is naturally located at the highest end of the mold. The metal runs down to the bottom of the mold and any air and gases t'apped in the mold escape through the vent 30 at the lower end. When the metal commences to solidify, it expands slightly, and if this expansion is greater than the expansion of the mold due to the transference of heat the cope and drag will be moved relatively to one another, so that they are not called upon to resist any force which would tend to burst them. In casting brakeshoes, the expansion of the metal on solidifying is very slight in the lateral and vertical directions, and in point of fact, owing to the position of the mold and the manner in which the metal accumulates therein, there is almost no expansion in these directions, but only in the longitudinal direction. Obviously, the only thing that prevents the cope from moving in the either a vertical or a longitudinal direction so that the expansion is transferred into or both. Owing to the position of the mold,

a very perfect casting is obtained. -The metal -which first enters the mold is that which forms the face. of the shoe. Ifthe metal stiffens on striking the cooler mold, the layer of molten metal above it operates to keep it soft and force it closely against the drag, so that a very smooth casting is obtained. As the metal runs quietly down through the mold any bubbles of air or gas, which have been carried in with the metal, have ample time to separate from the metal and are not imprisoned, as frequently oc curs when the brakeshoe is poured vertically. Another advantage of this method is that the shoe may be said to cool from the face toward the back, whereas with vertical pouring, the shoe cools from one end toward the other. The position in which the mold is arranged has numerous additional advantages; for example, any dross which may rise to the top of the metal will be found at the back of the shoe in place of toward one end,- so that the metal on the face of the shoe will be of even hardness throughout its length. There is in addition not nearly asmuch tendency for-the metal to force its way between the back strap and the cope or out through the opening 22, as would. be the case it the mold was vertically disposed. A; further advantage is that the cope may be lifted ofl the drag by an overhead hoist, without disturbing the drag, and will not require anything but its own weight to hold itin position when on the drag.

In practice, it is obvious that more than one mold will be used. The molds will be arranged in batteries, and the metal will be poured into them in succession. The number of molds in each battery will preferably be regulated, so that by the time the last mold of the battery is opened and the casting removed, the first mold will be sufficiently cooled for the insertion of a.

new back strap and for the reception of a fresh charge of molten metal. In this manner, the process of casting may be car ried on continuously without any loss of time. and without having a large number of molds idle. for considerable periods of time.

It will also be seen that by carrying on this method of manufacture in a continuous manner, the molds will after the first few castings have been made, reach a tempera.- ture which they will maintain with very little variation. This is of considerable advantage, as it insures all castings being made under exactly similar conditions.

While particular attention has been paid in the foregoing description to the casting of brake shoes, it must be understood that this is purely because brake shoes have been selected asian example, and for the purpose of illustrating the method, so that the method is not limited to the casting of brake shoes, but may be applied to the casting of many other articles.

Having thus described my invention, what I claim is:

1. A method of making strap back brakeshoes, eonsistingjn releasably maintaining the strap back tightly a ainst the upper part of a, permanent mold b and. removable from the exterior of the mold, and flowing molten metal under the strap.

2. A method of making strap back brakeshoes, consisting in holding a strap back tightly in the upper part of a mold by external means inserted through the mold, and flowing molten metal under the strap.

:3. A method of making articles having inserts of different material, which comprises holding the insert in an apertured mold by means inserted from the exterior of the mold through the. aperture thereof, temporarily filling the aperture around the holding means, and flowing molten metal into the mold.

y means applicable In Witness whereof I have hereunto set 

